Diene oligomers

The results of dT/dt and T measurements made during curing of two systems - macro(di-isocyanate) based on poly(tetraethylene glycol) and 2,4-toluylene diisocyanate cured by diamine (MDA) and epoxy diene oligomer cured by triethanol(amine titanate) are shown in Figs. 3.9 and 3.10, respectively. The monotonic increase in the parameters, monitored in the experiment,... 

Ilhan F, Rotello VM (1999) Thermoreversible polymerization. Formation of fullerene-diene oligomers and copolymers. J Org Chem 64 1455-1458... 

Development of a manufacturing process for diene oligomers belonging to a liquid rubber class with viscous liquids consistence allowed us to create a new class of conglomerate polymer composite materials—rubber concrete (RubCon). Rubber concrete is an advanced construction material created over the last few years. It is polymer concrete with a unique set of physical-mechanical, chemical, and technological properties that allow the creation of highly effective building structures and products. 

As several studies show, the best combination of physical, chemical, and technical parameters is exhibited by RubCon, based on diene oligomers without functional... 

It is necessary to note that this value exceeds the adhesion of furfurolacetate polymer concrete or usual cement concrete by approximately 10 times. Such high adhesion of the RubCon matrix to steel reinforcement is apparently related to the nature of the diene oligomer that is used as binder. 

FIGURE 2.81 (1) The diene oligomer vulcanizate viscosity-hardness relationship after... 

UP-637 and ED-20 cured by UP-0639 with and without addition of the low-molecular-weight rubber. As in systems based on diene oligomers, the integration of the rubber into oligomers based on UP-637 results in a peak in the temperature relationship of tan 6 at 213 K. Increase of the rubber content produces increase of the peak intensity only, without any practical change in the temperature at which tan 6 is maximal. 

Scheme 5.24) and diene oligomers also formed as by-products. Remarkably, Cjg-y-lactone 6 can be obtained in much higher yield from the C9-8-lactone 1 and butadiene in the presence of (C2H4)2Rh(acac)/PEt3. 

The first diene oligomer obtained industrially was oligobutadiene, made in Germany in the period between the two world wars under the trade name Plastikator-32 [35]. In 1950-1955 various technologies were worked out and, the ranges of application of liquid butadiene and liquid butadiene-styrene copolymers explored. These products encountered obstacles to commercial recognition. Thus, in this time span it was only such products as Budium (Du Pont de Nemours, La Rochelle, France) and Ricon (Richardson Co., Richmond, VA) that could be mar-... 

A method for the evaluation of gel permeation chromatograms obtained by analyzing mixtures of long-chain alkenes or diene oligomers have been proposed [78]. Mathematical relations were derived for proper calibration and calculation of the content of particular oligomers from the shape of the chromatograms. 

The checkers obtained erratic results in this step, possibly because of surface effects or trace impurities in the pressure vessel. In two other runs, only 16.8-18.8 g of crude product were obtained. In one case, high boiling oligomers were formed, but none of the desired product was produced. Impurities in the diene or dienophile did not appear to be the problem since runs which employed recrystallized 3-acetyl-2(3H)-oxazolone and redistilled 2,3-dimethyl butadiene also gave variable results. 

Acyclic diene molecules are capable of undergoing intramolecular and intermolec-ular reactions in the presence of certain transition metal catalysts molybdenum alkylidene and ruthenium carbene complexes, for example [50, 51]. The intramolecular reaction, called ring-closing olefin metathesis (RCM), affords cyclic compounds, while the intermolecular reaction, called acyclic diene metathesis (ADMET) polymerization, provides oligomers and polymers. Alteration of the dilution of the reaction mixture can to some extent control the intrinsic competition between RCM and ADMET. 

ADMET is quite possibly the most flexible transition-metal-catalyzed polymerization route known to date. With the introduction of new, functionality-tolerant robust catalysts, the primary limitation of this chemistry involves the synthesis and cost of the diene monomer that is used. ADMET gives the chemist a powerful tool for the synthesis of polymers not easily accessible via other means, and in this chapter, we designate the key elements of ADMET. We detail the synthetic techniques required to perform this reaction and discuss the wide range of properties observed from the variety of polymers that can be synthesized. For example, branched and functionalized polymers produced by this route provide excellent models (after quantitative hydrogenation) for the study of many large-volume commercial copolymers, and the synthesis of reactive carbosilane polymers provides a flexible route to solvent-resistant elastomers with variable properties. Telechelic oligomers can also be made which offer an excellent means for polymer modification or incorporation into block copolymers. All of these examples illustrate the versatility of ADMET. 

Figure 8.17 Copolymerization of telechelic oligomer 30 with a rigid aromatic diene.

Contrary to expectations, only an unusually small part of the diene exists in the conjugated form. Furthermore the formation of cyclohexane derivatives is noticeable. Their formation can be explained with the compounds listed on row 4 in Table 9. During the alkylation the monoolefin reacts on one side to LAB, on the other side to oligomers, and, depending on the excess of benzene, in part to the dialkylbenzenes found as byproducts in the so-called heavy alkylate (the residues of the raw alkylbenzene distillation). 

Bis-o-quinodimethanes have also been used to functionalize [60]-fullerene by Diels Alder reaction. An example is the preparation of main-chain polymers with incorporated [60]-fullerene units [48] illustrated in Scheme 2.20. Cycloaddition of bis-diene 50 generated in situ from bis-sulfone 49 with [60]-fullerene leads to an oligomer mixture 51. Another type of functionalization is based on the... 

Butadiene and isoprene give rise to mixtures of what are usually called telom-ers, namely 1 1 telomers between the amine and the 1,3-diene (trae hydroamination products), 1 2 telomers and even higher homologs together with oligomers of the diene as exemplified in Eq. (4.41). 

Reactions of conjugated 1,3-dienes, mainly butadiene and isoprene, catalyzed by transition metal complexes to form a number of linear and cyclic oligomers and telomers, are one of the most fascinating fields of research in the last 20 years. Extensive studies from academic and in-... 

If the oxo (or methano) bridges are not exclusively syn to one another in either the bis-dienophiles or bis-dienes, then the pressure-induced repetitive Diels-Alder reactions (proceeding again highly stereoselectively) produce rigid ribbon-type oligomers on a nanometer scale (Scheme 10 entry 1). Bis-diene 45 reacts less stereoselectively than bis-diene 44 and forms with bis-dienophiles such as 46 the ribbon-type oligomers 47... 

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